Soil Depth Profiles

Fig. 2. Clay recovery (wt %) from soils, depth profile (vertical scale 500 x exaggerated).

Soils (depth profiling) ICP-SFMS (Element) separation by ion exchange 87Sr, 86Sr, 207 Pb, 206 Pb 87Sr/s6Sr-0.08 % 207pb/2°6pb o.07% Prohaska et a/.155... 

The soil depth profile was sampled 600 m to the Southwest of the Hettstedt metallurgical works from a clayey soil (>35% clay) of the Wipper meadow. Fig. 9-12 shows that the heavy metal emission in the Hettstedt district originated from the copper metallurgical industry [UMWELTBUNDESAMT, 1991]. The heavy metal emission was at a maximum in 1983 and 1985 and is nowadays at a low level because of the closure of most of the emitters. As would be expected from the high values of heavy metal dust emission in recent years, high soil concentrations were found for the elements zinc, copper,... 

Soils (depth profiling) ICP-SEMS (Element) separation by Ion exchange 2Sr, Sr, 202 Pb, 200 Pb 82sr/8 >Sr-0.08 7o 207pb/206pb 0.077o Prohaska et a/. o... 

Preliminary research has shown that Brillouin fiber-optic sensing systems provide a possible method to detect leaks and third-party intrusion on a pipeline over distances of 25 km or more. Their intrinsic response to both temperature and mechanical strain allows for the separation of these parameters and the detection of anomalies in the scan profiles. In addition, the same sensor could be integrated into the pipeline system to detect possible ground movement relative to fixed reference points. Limited test results on surface loads associated with the intrusion of vehicles and people on a pipeline have demonstrated the sensitivity of the system and its ability to discriminate loads at different soil depths. 

Two commercial partial extraction techniques improve anomaly contrast in B horizon soil samples compared to aqua regia-ICPMS for Cu and Au. However, whereas the MMIsm and Bio LeachSM Cu profiles are similar, the MMIsm Au signal is much larger than that for Bio LeachSM. Analysis of samples at different depths down the B soil horizon profile indicates that the geochemical response from these methods is depth dependant. 

TokunagaTK, LiptonDS, Benson SM, Yee AW, Oldfather JM, Duckar EC, Johannis PW, HalvorsenKE (1991) Soil selenium fractionation, depth profiles and time trends in a vegetated site at Kesterson Reservoir. Water Air Soil Pollut 57 31-41... 

Figure 3 shows the pattern of tritium distribution on the 18A (southeastern) transect. The concentrations of tritium increase sharply with depth at all stations on the transect, and the peak tritium concentration occurs at a depth of 3 to 5 feet at all stations regardless of ejecta depth. In another transect of the ejecta field on the west side of the crater at 20A, shown in Figure 4, the tritium depth profiles show a similar pattern, and maximum tritium concentrations occur in the same zone, 2-5 feet. At a distance of 2000 feet from the crater lip, the depth of ejecta was 2-3 inches. The maximum concentration of tritium in soil water was at 3 feet at that site. 

Figure 4. Depth profiles of iil l) (PDB) versus soil depth, from three sites in the Mojave Desert, (a) SM-3 (1990 masl), (b) SM-2b (1550 masl), and (c) PaM-1 (300 masl), all from Quade et al. (1989a).

Figure 5. Depth profiles of soil temperature for a site at 4100 m in southern Tibet (see text) calculated using MAT from nearby Lhasa (3660 m) of 8°C and a local air-T lapse rate of 6 °C/km, a) showing modeled seasonal fluctuations in soil temperature at various depths, and (b) seasonal deviations from predicted 818Osc values at MAT.

Figure 7. 518Osc (PDB) of soil carbonate collected from 50 cm soil depth versus elevation (masl) from Holocene-age soils in the Mojave Desert (from Quade et al. 1989a). Soil carbonate collected on both limestone and non-limestone parent materials show die same approximate decrease with elevation of —5.5 %o/km. Soil profile values are the same as in Figure 4. The line denotes the 5 0 (PDB) predicted from local values from 32 rainfall collection sites in the Mojave Desert (518Omw (SMOW) = -0.0013...

Multivariate methods are useful for describing depth profiles of soils and detecting latent information about data sets which could not be easily discovered by univariate analysis. 

In general, the relationship between the concentration of a contaminant in the pore water and the total concentration in soil varies with soil depth due to variations in soil characteristics. Because soil samples in most experiments are taken in the upper soil layer, where at least the organic matter content is relatively high, the calculated available fraction of contaminants generally underestimates the actual average available fraction of contaminants for the whole unsaturated soil profile. 

Nesbitt H. W. and Muir I. J. (1988) SIMS depth profiles of weathered plagioclase and processes affecting dissolved A1 and Si in some acidic soils. Nature 334(6180), 336-338. 

Figure 21 shows the variation of soil water as a function of depth during a three-month period in 1991. Each panel represents a nest of soil water samplers at different positions on a hillslope. Some sites (NC2, NC4, and SC3) show a large range in throughout the depth profile. 

Cooper et al. (1994) have reported re-suspension studies on soils contaminated with plutonium during nuclear weapons tests by use of a mechanical dust-raising apparatus. Airborne dust was analysed in terms of mass and Am activities for particle sizes less than 7 pm. The AMAD was determined as 4.8-6 pm for re-suspended soil. Also, surface soil was characterised in the laboratory by means of sieving and microparticle classification, yielding mass and "Am activity distribution with respect to size. Data indicate the granularity of plutonium contamination at both major and minor trial sites. Depth profile analyses for undisturbed areas demonstrate that most (74% on average) of the americium and plutonium activity is found in the top 10 mm of soil. Plutonium and americium activities were found to be enhanced in the inhalable fraction over their values in the total soil, and the enhancement factors were similar in re-suspended dust and surface soil. Observed enhancement factors ranged from 3.7 to 32.5. 

---